Impact of bulk reduction on TiO2(1 0 0)/K

Photoelectron spectroscopy, low energy electron diffraction, and reflection high energy electron diffraction have been employed to probe the electronic and geometric structure of the TiO2(1 0 0)/K interface. Data have been obtained from two (1 0 0) oriented single crystal samples, which differ in their extent of bulk reduction. It is demonstrated that this parameter is important for both the electronic and geometric structure of ordered TiO2(1 0 0)/K surfaces, formed by annealing to ∼1000 K. Photoelectron spectra, recorded following this preparation, indicate that reduced Ti states are present for the less stoichiometric sample, which exhibits a 1−122 surface unit cell. In contrast, the other sample displays a c(2×2) overlayer, with no Ti reduction evidenced.